Interdependent Progression of Bidirectional Sister Replisomes in E. coli

Authors

Po Jui Chen
Anna B McMullin
Bryan J Visser
Qian Mei
Susan M Rosenberg
David Bates

Publication Date

1-9-2023

Journal

eLife

DOI

10.7554/eLife.82241

PMID

36621919

PMCID

PMC9859026

PubMedCentral® Posted Date

1-9-2023

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

Keywords

Escherichia coli, DNA Replication, Chromosomes, DNA, DNA-Binding Proteins

Abstract

Bidirectional DNA replication complexes initiated from the same origin remain colocalized in a factory configuration for part or all their lifetimes. However, there is little evidence that sister replisomes are functionally interdependent, and the consequence of factory replication is unknown. Here, we investigated the functional relationship between sister replisomes in Escherichia coli, which naturally exhibits both factory and solitary configurations in the same replication cycle. Using an inducible transcription factor roadblocking system, we found that blocking one replisome caused a significant decrease in overall progression and velocity of the sister replisome. Remarkably, progression was impaired only if the block occurred while sister replisomes were still in a factory configuration – blocking one fork had no significant effect on the other replisome when sister replisomes were physically separate. Disruption of factory replication also led to increased fork stalling and requirement of fork restart mechanisms. These results suggest that physical association between sister replisomes is important for establishing an efficient and uninterrupted replication program. We discuss the implications of our findings on mechanisms of replication factory structure and function, and cellular strategies of replicating problematic DNA such as highly transcribed segments.